I understand that a floating magnet has "weight", but if for example I had two 1kg magnets and a set of scales and I placed one of these magnets on the scales with the other floating above it what would the scales read? 1kg or 2kg or something completely different (numerous practical problems of keeping the floating magnet inside the others magnets field aside)?
Professor Yann Chemla received his PhD. in physics from the University of California, Berkeley in 2001. As an experimentalist in applied superconductivity, he developed an interest in biology through his study of magnetotactic bacteria with a superconducting magnetometer (Chemla et al., Biophys J., 1999), and the development of a biosensor based on functionalized magnetic nanoparticles (Chemla et al., PNAS, 2000). Prof. Chemla made the “leap” to biophysics as a postdoctoral fellow, moving down the hall to Prof. Carlos Bustamante’s laboratory at Berkeley. There, he learned the techniques of single-molecule manipulation and used an optical trap to study viral DNA packaging (Chemla et al., Cell, 2005). In 2005, he received one of the prestigious Career Awards at the Scientific Interface (CASI) from the Burroughs-Wellcome Fund. He joined the Department of Physics at Illinois in January 2007.
The cell is a factory of complex molecular structures that carry out specialized mechanical tasks and that behave remarkably like machines. Molecular motors, as they are called, are involved in such diverse processes as replicating the genome or transporting cargo across the cell, typically moving in discrete steps along a track ó actin, microtubules, or DNA itself ó converting chemical energy into mechanical work. A broad area of interest in my laboratory will be understanding the mechanism by which these molecular machines operate, and specifically, the process of mechano-chemical conversion.
Biophysical techniques that can detect such processes at the level of a single molecule are extremely powerful, since they are not subject to the averaging artifacts of traditional bulk biochemical methods. Optical traps, or ďoptical tweezers,Ē which utilize the force generated by focused laser light to manipulate microscopic objects, have been used extensively to measure the movements and forces exerted by individual molecular motors.
Recently, advances to this technique have made it possible to resolve motions on the scale of a single base pair of DNA, or only 3.4Ň (see for example, Moffitt et al., PNAS, 2006). These high-resolution optical trapping techniques have the potential to reveal, for the first time, the stepwise motions of a host of molecular motors that translocate along or interact with nucleic acids and proteins. Access to this length scale should lead to a more detailed and refined understanding of many fundamental processes.
Students in my laboratory will work on all facets of research in this area: design and construction of instrumentation, development of biological systems for single-molecule manipulation, and quantitative analysis and modeling of collected data. Interested students and postdocs with backgrounds in physics, biology, chemistry, or related fields are welcome to contact me.
161 Loomis Laboratory
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